How the Test is Performed

Immediately after the birth of your baby, the umbilical cord is clamped and cut. If cord blood is to be drawn, another clamp is placed 8 to 10 inches away from the first, then the isolated section is cut and a blood sample is collected into a specimen tube.

How to Prepare for the Test

No special preparation is necessary for this test.

How the Test Will Feel

You will not feel anything beyond the normal birthing process.

Why the Test is Performed

Cord blood testing is done to determine the following:

• Bilirubin levels
• Blood culture (if an infection is suspected)
• Blood gases, to evaluate the oxygen, carbon dioxide, and pH levels
• Blood sugar level
• Blood type and Rh
• Complete blood count (CBC)
• Platelet count

Normal Results

Normal values mean that all items evaluated are within normal range.

What Abnormal Results Mean

A low pH (less than 7.04 to 7.10) means there are higher levels of acids in the baby's blood. This might occur when the baby does not get enough oxygen during labor. One reason for this could be that the umbilical cord was compressed during labor or delivery.

A blood culture that is positive for bacteria indicates septicemia.

High levels of blood sugar (glucose) in the cord blood may be found if the mother has diabetes. The newborn will be watched for hypoglycemia (low blood sugar) after delivery.

High levels of bilirubin could be due to infections that the baby gets before birth, including:

• Congenital CMV
• Congenital hepatitis
• Congenital rubella
• Congenital toxoplasmosis

Other possible causes include:

• Dubin-Johnson syndrome
• Jaundice in the mother
• Mother taking sulfa drugs during pregnancy
• Rh incompatibility

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Considerations

Most hospitals routinely collect cord blood for testing at birth, since it is relatively convenient and the only time possible to collect such blood. Besides cord blood testing, cord blood can be used to treat certain types of bone marrow-related cancers. Some parents may choose to save (bank) their child's cord blood for this and other, future medical purposes.

Cord blood banking for personal use is done by private companies, which charge for the service. Cord blood can also be donated to your local blood bank for use by others as needed to treat leukemia and other cancers.

References

American Academy of Pediatrics Section on Hematology/Oncology, American Academy of Pediatrics Section on Allergy/Immunology, Lubin BH, Shearer WT. Cord blood banking for potential future transplantation. Pediatrics 2007;119(1):165-170.

Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007.

Update Date: 4/5/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.